<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>组合式下拉菜单</title>
<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css">
<link rel="stylesheet" href="style.css">
</head>
<body>
  <div class="btn-group">
      <button class="btn btn-default dropdown-toggle" data-toggle="dropdown" type="button">按钮下拉菜单<span class="caret"></span></button>
    <ul class="dropdown-menu">
    	<li><a href="##">按钮下拉菜单项</a></li>
    	<li><a href="##">按钮下拉菜单项</a></li>
    	<li><a href="##">按钮下拉菜单项</a></li>
    	<li><a href="##">按钮下拉菜单项</a></li>
    </ul>
  </div>
  <script src="http://libs.baidu.com/jquery/1.9.0/jquery.js"></script>
  <script src="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"></script> 
</body>
</html>